wathV (FLATHEAD)
DP
Project 2.10 =~ Verification of Washdown Effectiveness as a Shipboard
Radiological Countermeasure - M, M, Biggers
'
Objectives
Operation of YAG's and LST to be stationed in fallout area
RadSafe support for NRDL Projects
Washdown evaluation
Procedure and Results - Ship Operations
The project ships, YAG=39, YAG-40, and LST-61l, successfully completed
their mission on the
FLATHEAD) shot.
Precise information in ships
position and other operational information has been given Project 2.63 for
inclusion in their reports,
YAG-
"
erations
YAG=39 encountered fallout at 1030 of D-day (12 Jume).
At 1100,
when the gamma radiation intensity had increased by 2 mr/hr, the ship
was closed and washdown activated.
The radiation level peaked at 1800,
Deday, with an intensity of 140 - 150 mr/hr. on the unwashed deck forward,
and 10 = 14 mr/hr on the unwashed deck aft,
was 8.4 mr/hr.
Peak intensity on the bridge
Fallout apparently stopped at the same time it peaked (1800).
Washdown was secured at 1950, the ship partially opened at 2115 and complet-
ely opened at 2400.
YAG-LO Operations:
YAG-40 encountered fallout (i.e. a 2 mr/hr increase in gamma radiation intensity) at about 1415 on D-day,
Watch was transferred to the
bridge and the ship closed except for several hatches,
When the radiation
intensity reached 20 to 30 mr/hr at 1600, the engine room hatch was closed
and the washdown system was activated,
COPIED DOE
bate RO
- 39 -
Peak intensity occurred at about
aU